1. Field of the Invention
This invention relates to a toner container used to supply toner to a development unit of an image forming apparatus and relates to the image forming apparatus to which the toner container is attached.
2. Description of the Related Art
An image forming apparatus, such as a copying machine, a printer, or a fax machine, includes a toner supply device for replenishing a development unit with toner. This type of toner supply device comprises a cylindrical toner bottle that contains toner, a holding means for holding the toner bottle substantially horizontally in a state where the toner bottle is in connection with a toner-introducing portion of the development unit, and a rotation drive means for rotating the held toner bottle on its center axis. The toner bottle is of a screw bottle type having a spiral rib on the inner surface of the bottle. When the toner bottle is rotated by the rotation drive means, the toner in the bottle is conveyed toward a toner discharge opening of the bottle along the spiral rib and is discharged therefrom. In this way, the development unit is replenished with the toner.
The image forming apparatus (e.g., copying machine) further includes a heat source, such as a fuser. For this reason, there are instances where the toner in the bottle melts with the heat of the heat source. Even when the toner does not melt therewith, the toner bottle is intensely heated. This lowers the fluidity of the toner in the bottle, thus retarding the toner supply and causing no little toner to adhere to the inner surface of the bottle. Therefore, there occur disadvantages, such as an increase in quantity of the remaining toner in the bottle at the toner end. The disadvantages occur especially in a compact image forming apparatus, generally called a process cartridge, having a construction in which a photoconductor and its peripheral equipment are contained in a compact case in the form of a unit. The reason is that, in the compact image forming apparatus, a toner supply device and a heat source are close to each other.
Conventionally, in order to solve the disadvantages, there are known a developer container disclosed by Japanese Patent Application Laid-Open Publication No. Hei 3-271782, a toner supply container disclosed by Japanese Patent Application Laid-Open Publication No. Hei 6-194950, and so forth. The conventional container has a double construction comprising an outer cylindrical portion and an inner cylindrical portion so that the toner in the container is prevented from melting or hardening under the influence of heat, moisture, and the like.
The aforementioned toner supply device has a simple construction and therefore is manufactured at small cost. However, since the toner is supplied in a state where the toner bottle is held substantially horizontally, the toner discharge opening must be opened or closed with a stopper when supplying the toner. Therefore, it is required to mount a lid member of the toner bottle, an opening-and-closing mechanism for opening and closing the toner discharge opening with the stopper, and the like, on the side of the image forming apparatus. This is an obstacle to making the image forming apparatus more compact and reducing the manufacturing costs. Additionally, the conventional toner bottle of the screw bottle type cannot control a toner replenishment by itself and cannot singly serve as a toner supply device. For this reason, there is a need to mount a toner replenishment control means, such as a toner hopper, on the side of the image forming apparatus.
Generally, this type of toner supply device further has a seal member for preventing toner leakage. Especially, the seal member disposed at a sliding portion requires durability. However, if a polyurethane foam (i.e., sponge) of low cost, for example, is used as the seal member, there is a fear that the sealing power thereof will decline because of long-term use of the device. Therefore, in the conventional toner supply device, the sealing power of the sealing member must be retained according to the life of the device. In other words, a seal member of low cost, such as a sponge, cannot be used.
A toner container in which a toner bottle is provided with a lid member has been already proposed by the present applicant. Because of being shaped like a cylinder in outward appearance, this toner bottle is liable to roll when placed horizontally and is restricted in handling. Additionally, because of being generally made of polyethylene, this type of toner bottle is small in rigidity, and a fixing portion of the lid member is liable to be deformed. In other words, the toner bottle does not have sufficient mounting strength.
On the other hand, a toner container having a double construction comprising an outer cylindrical portion and an inner cylindrical portion is recyclable by refilling it with new toner. However, since the outer and inner cylindrical portions are formed integrally with each other, or since the outer cylindrical portion is provided with a toner supply portion, the whole container including the outer cylindrical portion is contaminated with toner during a single use. Therefore, in order to use it again, it is required to clean almost all the constituent parts including the outer cylindrical portion. Thus, the toner container having this type of double construction is unsuitable for recycling.
Additionally, in the conventional toner container, all the combined parts of the outer cylindrical portion must be sealed by welding, gluing, or adhesion of a seal member so as to prevent toner leakage. Thus, the toner container is difficult to have a simple construction. Additionally, when the conventional toner container is refilled with new toner, the new toner must be provided from a toner-introducing opening of the outer cylindrical portion by the use of exclusive equipment. Thus, the toner container is inferior in productivity.
Additionally, in a toner container provided with a toner supply mechanism, such as an agitator, or a toner container provided with a tapping member whose vibrations prevent toner from adhering to the inner surface of the container, there is a problem in that a noise is produced when the agitator or tapping member operates.